topic Re: mx6ul tamper pin to gpio in i.MX Processors

mx6ul tamper pin to gpio

jiangyaqiang — Tue, 15 Dec 2015 13:40:02 GMT

HI :

How can i config a tamper pin to a gpio ? for example , how to config IOMUXC_SW_CTL_PAD_SNVS_TAMPER0 to gpio5_0.

refer to the document of mx6ul IMX6ULSRM.pdf , I know that , it has to config TAMPER_PIN_DISABLE[1:0]., which is found in

chapter 5 "Fusemap": 0x430[21:20]. but how to access it ?

Could anyone please give me a hand ? I'm confuse about it for sometimes .

Re: mx6ul tamper pin to gpio

Yuri — Wed, 16 Dec 2015 04:18:40 GMT

Hello,

You may use U-boot to read / write (once) fuses.

For example, u-boot command to read TAMPER_PIN_DISABLE is

=> fuse read 0 3

Definition of TAMPER_PIN_DISABLE[1:0] are as following :

00 - enabled, TAMPER0-9 used as TAMPER detection pins.

01 - disabled TAMPER2-4 and TAMPER7-9 used as GPIO.

10 - disabled TAMPER0-1 and TAMPER5-6 used as GPIO.

11 - disabled TAMPER0-9 used as GPIO.

So, for the mentioned U-boot command, If bit [21:20] is 11, then all the ten
tamper pins are programmed to GPIO mode.

Have a great day,
Yuri

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Re: mx6ul tamper pin to gpio

jiangyaqiang — Wed, 16 Dec 2015 04:27:18 GMT

Thank you very much

Re: mx6ul tamper pin to gpio

ericnelsonaz — Fri, 12 Aug 2016 16:20:29 GMT

Hi Yuri,

I'm having trouble getting this to work.

Bits 20-21 are set to 11 on my system:

=> fuse read 0 3

Reading bank 0:

Word 0x00000003: 7031006e

But I'm unable to change SNVS_TAMPER1 to alt 5 (GPIO) using register IOMUXC_SW_MUX_CTL_PAD_SNVS_TAMPER5:

=> mm 020e0020

020e0020: 00000010 ? 15

020e0024: 00000000 ? -

020e0020: 00000010 ? =>

I'm running on an i.MX6UL, rev 1.1:

CPU: Freescale i.MX6UL rev1.1 528 MHz (running at 396 MHz)

CPU: Automotive temperature grade (-40C to 125C) at 36C

Re: mx6ul tamper pin to gpio

ericnelsonaz — Fri, 12 Aug 2016 17:03:29 GMT

Hmmm. The pin is acting like a GPIO even though a read-back of the mux register doesn't show ALT5.

Re: mx6ul tamper pin to gpio

Yuri — Mon, 15 Aug 2016 03:41:40 GMT

Hello,

"If TAMPER_PIN_DISABLE[1:0] fuse is programmed to "11 - disabled TAMPER0-9 used as GPIO",

then the tamper pins are in gpio mode, you do not need to configure iomux."

Regards,

Yuri.

Re: mx6ul tamper pin to gpio

ericnelsonaz — Mon, 15 Aug 2016 13:29:07 GMT

Thanks Yuri

Re: mx6ul tamper pin to gpio

qinghuazhu — Tue, 23 Aug 2016 09:16:12 GMT

Hello,

How do you set the value of Bits 20-21.Can you tell me your command?

And how do you know TAMPER_PIN_DISABLE is Bank 0 Word 3?

which document descript the register?

Thanks.

Re: mx6ul tamper pin to gpio

ericnelsonaz — Tue, 23 Aug 2016 12:41:43 GMT

Hi Zhu,

The TAMPER_PIN_DISABLE field is found in the reference manual on page 214 (Table 5-9), though you can't search for it directly because of word wrap.

Search instead for "TAMPER_PIN_DIS".

Re: mx6ul tamper pin to gpio

qinghuazhu — Tue, 23 Aug 2016 12:59:10 GMT

Is it the "35.5.14 Value of OTP Bank0 Word3 (Configuration and Manufacturing Info.) (OCOTP_CFG2)"?

I can't set its value use uboot command:

=> mw 0x21bc430 0x0030002f

=> fuse read 0 3

Reading bank 0:

Word 0x00000003: 0000002f

=> md 0x21bc430

021bc430: 0000002f /...

I don't know how to change its value.

Can you help me?

Re: mx6ul tamper pin to gpio

ericnelsonaz — Tue, 23 Aug 2016 14:51:40 GMT

Hi Zhu,

I don't think anyone wants to say (myself included), because you can brick a device, but the command to write fuses is "fuse prog", and to set those bits, you might do this:

=> fuse prog 0 3 0x0030002f

Re: mx6ul tamper pin to gpio

qinghuazhu — Wed, 24 Aug 2016 09:39:07 GMT

Hi Eric,

Thanks very much.

Unfortunately, I'm using G3, I can't use tamper pin as nomal GPIO.

and may you explain "tamper gpio" for me?

What does it mean?

Thanks.

Re: mx6ul tamper pin to gpio

ericnelsonaz — Wed, 24 Aug 2016 13:45:24 GMT

Hi Zhu,

Sorry, but I'll have to refer to others for the explanation of tamper gpio.

Re: mx6ul tamper pin to gpio

qinghuazhu — Thu, 25 Aug 2016 01:14:01 GMT

做工业级应用，一般会选择G2版本，如果使用了G3版本，则其以下GPIO只能做tamper GPIO,不能做普通的GPIO：
CTL_PAD_SNVS_TAMPER0～CTL_PAD_SNVS_TAMPER9 10个GPIO。
可以通过烧写掉以下fuse来将其设置为一般的GPIO:
G3 version CPU is for POS machine design, not as the G2 for industry, which the follow fuse is 00 and need you burn it to 11 to enable tamper0-9 to normal gpio, Pls check your reference manual
TAMPER gpio 是Pos机上用的，检测攻击，数据会自毁。